Interspecific and geographical differences in anticoagulant rodenticide residues of predatory wildlife from the Mediterranean region of Spain

Abstract

We studied the prevalence of anticoagulant rodenticides (ARs) in the liver of 344 individuals representing 11 species of predatory wildlife that were found dead in the Mediterranean region of Spain (Catalonia and Majorca Island). Six different ARs (brodifacoum, bromadiolone, difenacoum, flocoumafen, difethialone, warfarin) were found in the liver of 216 (62.8%) animals and >1 AR co-occurred in 119 individuals (34.6%). The occurrence of ARs was positively correlated with the human population density. Catalonia and Majorca showed similar prevalence of AR detection (64.4 and 60.4%, respectively), but a higher prevalence was found in the resident population of Eurasian scops owl (Otus scops) from Majorca (57.7%) compared to the migratory population from Catalonia (14.3%). Birds of prey had lower levels of bromadiolone than hedgehogs, whereas no difference was found for other ARs. The risk of SGAR poisoning in wild predators in NE Spain is believed to be elevated, because 23.3% of the individuals exhibited hepatic concentration of ARs exceeding 200ng/g.